1. Field of the Invention
This invention relates to a semi-transmitting reflective plate, a reflective plate, a semi-transmitting polarizer and a reflective polarizer to be used in a liquid crystal display (hereinafter sometimes abbreviated as “LCD”), and a liquid crystal display using the same.
2. Description of the Related Art
LCDs have been used in desktop computers, electronic watches, personal computers and word processors, and a demand for them has sharply been increased in recent years. Thus, production growth of semi-transmitting reflective displays for portable phones and personal portable information terminals is remarkable.
In order to improve display performance of LCD, a semi-transmitting polarizer comprising a polarizer having laminated thereon a semi-transmitting reflective plate is provided usually on the back side of a liquid crystal cell and, as a display method, there has been employed a method in which, in the case of using the liquid crystal display under a comparatively bright atmosphere, an incident light from watching side (display side) is reflected to display an image whereas, in the case of using under a comparatively dark atmosphere, an image is displayed using a built-in light source such as a backlight provided on the back side of the semi-transmitting polarizer. That is, the semi-transmitting polarizer can save energy for a light source such as a backlight under a bright atmosphere, while using a built-in light source under a comparatively dark atmosphere, thus being useful for formation of a liquid crystal display.
However, the reflective plate has been formed by bonding and laminating on a resin substrate or by deposition or sputtering, and has been used by bonding and laminating on an optical film such as a polarizer. FIG. 2 is a schematic cross section showing an example of the constitution of a conventional semi-transmitting reflective plate or a conventional reflective plate. A semi-transmitting reflective layer or a reflective layer (conductor) 13 composed of a metal thin film is formed on a light-transmitting high-molecular substrate 11 composed of a resin (insulator) such as PET, and an adhesive layer (insulator) 14 is formed thereon to constitute a semi-transmitting plate or reflective plate 15. Therefore, the structure of sandwiching between the insulators is liable to retain static electricity, which might be the cause of a fire or electric troubles. Also, in view of the character of the product, “a protective sheet having a releasable adhesive” (hereinafter abbreviated as “SPV”) is often bonded and laminated to the back surface of the substrate, and hence there has been involved the problem that mere coating of a surfactant on the substrate results in removal of the surfactant upon bonding and releasing the SPV.